On Wed, 2025-03-26 at 19:36 +0000, Yosry Ahmed wrote:
> Now that the ASID to vCPU/VMCB tracking was moved out of pre_sev_run(),
> the only remaining pieces are:
> (a) Checking for valid VMSA.
> (b) Assigning svm->asid.
> (c) Flush the ASID if the VMCB is run on a different physical CPU.
>
> The check in (c) is already being done in pre_svm_run(), and so is
> redundant. (a) and (b) are small enough and probably do not warrant a
> separate helper (and (b) will be going way soon), so open-code the
> function into pre_svm_run() and remove it.
>
> Signed-off-by: Yosry Ahmed <yosry.ahmed@xxxxxxxxx>
> ---
> arch/x86/kvm/svm/sev.c | 28 ----------------------------
> arch/x86/kvm/svm/svm.c | 16 ++++++++++++++--
> arch/x86/kvm/svm/svm.h | 1 -
> 3 files changed, 14 insertions(+), 31 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 3ef0dfdbb34d2..1742f51d4c194 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -3451,34 +3451,6 @@ void sev_es_unmap_ghcb(struct vcpu_svm *svm)
> svm->sev_es.ghcb = NULL;
> }
>
> -int pre_sev_run(struct vcpu_svm *svm, int cpu)
> -{
> - struct kvm *kvm = svm->vcpu.kvm;
> - unsigned int asid = sev_get_asid(kvm);
> -
> - /*
> - * Reject KVM_RUN if userspace attempts to run the vCPU with an invalid
> - * VMSA, e.g. if userspace forces the vCPU to be RUNNABLE after an SNP
> - * AP Destroy event.
> - */
> - if (sev_es_guest(kvm) && !VALID_PAGE(svm->vmcb->control.vmsa_pa))
> - return -EINVAL;
> -
> - /* Assign the asid allocated with this SEV guest */
> - svm->asid = asid;
> -
> - /*
> - * Flush guest TLB if the VMCB was executed on a differet host CPU in
> - * previous VMRUNs.
> - */
> - if (svm->vcpu.arch.last_vmentry_cpu == cpu)
> - return 0;
> -
> - vmcb_set_flush_asid(svm->vmcb);
> - vmcb_mark_dirty(svm->vmcb, VMCB_ASID);
> - return 0;
> -}
> -
> #define GHCB_SCRATCH_AREA_LIMIT (16ULL * PAGE_SIZE)
> static int setup_vmgexit_scratch(struct vcpu_svm *svm, bool sync, u64 len)
> {
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index e6e380411fbec..ce67112732e8c 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -3649,8 +3649,20 @@ static int pre_svm_run(struct kvm_vcpu *vcpu)
> svm->current_vmcb->cpu = vcpu->cpu;
> }
>
> - if (sev_guest(vcpu->kvm))
> - return pre_sev_run(svm, vcpu->cpu);
> + if (sev_guest(vcpu->kvm)) {
> + /* Assign the asid allocated with this SEV guest */
> + svm->asid = sev_get_asid(vcpu->kvm);
> +
> + /*
> + * Reject KVM_RUN if userspace attempts to run the vCPU with an invalid
> + * VMSA, e.g. if userspace forces the vCPU to be RUNNABLE after an SNP
> + * AP Destroy event.
> + */
> + if (sev_es_guest(vcpu->kvm) &&
> + !VALID_PAGE(svm->vmcb->control.vmsa_pa))
> + return -EINVAL;
> + return 0;
> + }
>
> /* FIXME: handle wraparound of asid_generation */
> if (svm->current_vmcb->asid_generation != sd->asid_generation)
> diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
> index ca38a233fa24c..3ab2a424992c1 100644
> --- a/arch/x86/kvm/svm/svm.h
> +++ b/arch/x86/kvm/svm/svm.h
> @@ -760,7 +760,6 @@ void avic_refresh_virtual_apic_mode(struct kvm_vcpu *vcpu);
>
> /* sev.c */
>
> -int pre_sev_run(struct vcpu_svm *svm, int cpu);
> void sev_init_vmcb(struct vcpu_svm *svm);
> void sev_vcpu_after_set_cpuid(struct vcpu_svm *svm);
> int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in);
Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Best regards,
Maxim Levitsky
